Patients with urological symptoms are diagnosed based on clinical features and routine diagnostics. Urodynamic tests help to evaluate functional and anatomical abnormalities of the lower urinary tract. The most common tests are cystometry, uroflowmetry, urethral pressure profile, and leak point pressure. Imaging may be used in combination to diagnose underlying pathologies and is often used to assess for anatomical obstructions or abnormalities (e.g., urinary obstructions caused by kidney stones, renal masses).
Procedures in urology include those involving the kidneys (e.g., percutaneous nephrolithotomy), ureters (e.g., ureteral stenting), bladder (e.g., transurethral resection of bladder tumor), prostate (e.g., transurethral resection of the prostate), penis (e.g., circumcision), and scrotum (e.g., vasectomy), as well as infertility procedures (e.g., testicular sperm extraction).
Urodynamic studies use the characteristics of urinary flow (pressure and flow rate at various points during micturition and at rest) to evaluate the functional and anatomical abnormalities of the lower urinary tract.
- Bladder is filled with water through a urethral catheter at a steady rate
- The vesical pressure is measured through this urethral catheter, while the intraabdominal pressure is measured via a vaginal or rectal pressure catheter
- The detrusor pressure is the difference in pressure between these two catheters
- Description: an objective, noninvasive test used in the evaluation of patients with suspected bladder outlet obstruction
- Patient is asked to void into a funnel that measures the volume and rate of urine flow.
- Measures the volume of urine voided over time
- Normal: a continuous, single bell-shaped curve with urine volume > 200 mL (over 15–30 seconds) and at a rate > 15 mL/sec
- Abnormal: an abnormal curve or urine volume at a rate < 15 mL/sec
Pressure-flow study 
Urethral pressure profile
- Procedure: A specialized urethral catheter, mounted with microtransducers, is withdrawn at a slow and steady rate from the bladder until it exits the external urethral meatus.
Leak point pressure
- Assesses intrinsic sphincter function (but during dynamic testing, unlike urethral pressure profile testing)
- Determines the intravesical pressure required to produce urine leakage in the presence of increased abdominal pressure (i.e., during detrusor contraction ) and the absence of
- May be performed during cystometry
Postvoid residual volume
- Description: measures the volume of urine that remains in the bladder after voiding
- Procedure: : may be performed using straight catheterization or ultrasound of the bladder
- Interpretation: A postvoid residual volume < 50 ml is normal.
- Description: a procedure that studies the electrical potentials of depolarized muscle, specifically the neural pathways involved in micturition (by evaluating the segment of the sacral spinal cord involved)
- Indication: to determine neurological abnormalities of the bladder (e.g., hypotonic bladder)
- Procedure: Electrodes or a concentric needle are inserted into the urethral sphincter.
- Renal: visualization of renal tumors, renal cysts, nephrolithiasis, hydronephrosis
- Bladder: bladder wall thickness, bladder calculi, tumors, urinary retention
- Prostate; : to estimate prostate volume, shape, echogenicity, and prostatic abscesses or masses
- Scrotal and penile: to evaluate for testicular torsion, cryptorchidism, trauma, testicular tumors, varicocele, and epididymitis.
- Description: a diagnostic procedure in which radioisotopes are used to assess the anatomy and function of the kidneys
Procedure: IV administration of technetium (Tc-99m pertechnetate/gamma emitter) and measurement of its distribution in the body with a gamma camera
Static renal scintigraphy: a diagnostic test in which a radiotracer that is retained by the renal cortex is used to assess renal function as well as the degree of structural damage to the renal cortex
- Injection of Tc-99m DMSA (Tc-99m dimercaptosuccinic acid; an injectable radioactive gamma-emitter dye that rapidly accumulates in the renal parenchyma and very small amounts are eliminated from the kidney)
- Imaging is performed ∼ 3 hours after injection, when the dye has reached the kidneys for renal clearance.
- Dynamic renal scintigraphy: a diagnostic test in which a radiotracer that is excreted by the kidney is used to assess renal perfusion as well as urine flow in the urinary tract
- Static renal scintigraphy: a diagnostic test in which a radiotracer that is retained by the renal cortex is used to assess renal function as well as the degree of structural damage to the renal cortex
Voiding cystourethrogram 
- Description: a diagnostic procedure used to determine the degree of vesicoureteral reflux and detect morphological abnormalities
Intravenous urography (excretory urogram, IV pyelogram) 
- Description: a diagnostic procedure that involves intravenous contrast agent and x-rays to provide images of the genitourinary tract
- Indication: visualization of renal excretion and the course of the ureters
- Description: an imaging study that uses CT with intravenous contrast to assess the anatomy and, to a certain degree, function of the urinary collecting system, renal calyces, ureters, and bladder
- Indications: a first-line imaging test to assess for genitourinary abnormalities (e.g., malignancy, stricture)
- Procedure: CT with contrast dye injected intravenously
- Description: a diagnostic test in which a contrast agent is injected into the urethra to evaluate for urethral injuries and disorders via x-ray
- Indication: suspected anatomical and functional lesions of the urethra (e.g., urethral stricture, injuries)
Retrograde CT cystography
- Description: imaging modality using computed tomography to visualize the bladder after retrograde filling with contrast agent
- Indication: evaluation of the bladder for postoperative leakage or rupture following trauma
- Procedure: CT after contrast dye is injected into the bladder via the urethra
- Description: A diagnostic procedure in which x-rays are taken as a water-soluble contrast agent is injected in the ureter via cystoscopy
- Contraindications to IV/CT urography
- Secondary study to confirm or further characterize findings
- Description: an endoscopic procedure in which a thin tube with a light and a camera is inserted through the urethra into the bladder, allowing for visualization of the urethra, bladder, and ureteral orifice
- Suspected interstitial cystitis, gynecological malignancies, endometriosis
- Recurrent urinary tract infections
- Urinary incontinence or overactive bladder
- Urinary tract injuries (traumatic or iatrogenic)
- Urinary obstruction
- Injection of therapeutic drugs (e.g., botulinum toxin for urinary incontinence)
- Procedure: A flexible or rigid cystoscope is inserted into the urethra using an electrolyte-containing irrigation fluid or sterile water.
- Description: placement of a catheter into the bladder via the urethra or percutaneously through the suprapubic abdominal wall
- Clinical applications
Types of bladder catheterization
- (e.g., with a )
- Description: : a surgical procedure that involves insertion of a catheter through the abdominal wall with placement in the bladder
- Percutaneous urinary catheter insertion above the pubic symphysis
- May be used intermittently or left in place to continuously drain urine
- Peritoneal perforation
- Injury to surrounding organs
- Description: a urologic procedure that involved insertion of a thin, hollow tube into the ureter to enable drainage of fluid from the renal pelvis into the bladder
- Contraindications 
Percutaneous nephrostomy 
- Description: a urologic procedure that involves the insertion of a pigtail catheter (nephrostomy tube) into the dilated renal pelvis
- Contraindications: uncorrectable coagulopathy